Arc suppression device, system and methods for liquid insulated electrical apparatus

Abstract

Arc suppression systems, devices and methods for avoiding undesirable arcing conditions inside a liquid-filled tank of a high-voltage electrical apparatus.

1 . An arc suppression system for a high-voltage electrical apparatus including at least one electrical component immersed in a liquid dielectric fluid, the arc suppression device comprising:
 a contact assembly comprising a line contact, a ground contact spaced from the line contact, and a movable contact mounted stationary to the line contact for normal operation of the electrical component; and   a stored energy element adapted to position the movable contact to complete an electrical connection between the line contact and the ground contact when the electrical component fails and generates an electrical arc of a designated magnitude and duration.   
   
   
       2 . The arc suppression system of  claim 1 , wherein the stored energy element comprises a squib. 
   
   
       3 . The arc suppression system of  claim 1 , wherein the stored energy element comprises a spring loaded mechanism. 
   
   
       4 . The arc suppression system of  claim 1 , wherein the stored energy element comprises a container containing a high-pressure gas. 
   
   
       5 . The arc suppression system of  claim 1 , further comprising a sensor configured to detect an arc flash. 
   
   
       6 . The arc suppression system of  claim 1 , further comprising a sensor detecting a current flow through the electrical component. 
   
   
       7 . The arc suppression system of  claim 1 , further comprising a controller, the controller operatively connected to the stored energy element, and the stored energy element responsive to the controller to position the movable contact when a failure of the electrical component is detected. 
   
   
       8 . The arc suppression system of  claim 7 , wherein the controller is configured to operate the stored energy element in response to a monitored current level for the line contact, a detected arc flash, and a detected arc duration. 
   
   
       9 . The arc suppression system of  claim 1 , further comprising a power supply, wherein the power supply is selected from the group of a battery, a fuel cell, an electrostatic couple, a capacitor and a power harvesting device. 
   
   
       10 . The arc suppression system of  claim 1 , wherein the apparatus comprises a power distribution transformer. 
   
   
       11 . The arc suppression system of  claim 1 , wherein the apparatus comprises switchgear. 
   
   
       12 . The arc suppression system of  claim 1 , wherein the apparatus includes a protective element. 
   
   
       13 . The arc suppression system of  claim 1 , wherein the apparatus comprises a high-voltage bushing, the arc suppression device connected to the bushing. 
   
   
       14 . The arc suppression system of  claim 1 , wherein the liquid dielectric fluid comprises a mineral oil, a vegetable oil, a polyolester fluid, a silicone fluid, or mixtures thereof, or other insulative fluids known in the art. 
   
   
       15 . An arc suppression system for a high-voltage electrical apparatus including a tank and at least one electrical component immersed in a liquid dielectric fluid within the tank, the arc suppression device comprising:
 a controller;   a light detecting sensor coupled to the controller and located to detect a presence of electrical arcing in the tank;   a current sensor coupled to the controller and monitoring a current flow to the electrical component; and   an arc suppressor device connected to the apparatus and responsive to the controller to complete a circuit path to electrical ground and extinguish the arcing when the monitored current exceeds a specified level and when the detected arcing exceeds a specified duration.   
   
   
       16 . The arc suppression system of  claim 15 , wherein the arc suppressor device comprises a contact assembly comprising a line contact, a ground contact spaced from the line contact, and a movable contact mounted stationary to the line contact for normal operation of the electrical component. 
   
   
       17 . The arc suppression system of  claim 15 , further comprising a stored energy element adapted to position the movable contact to complete an electrical connection between the line contact and the ground contact when the specified current level and the specified duration are met. 
   
   
       18 . The arc suppression system of  claim 15 , further comprising a power supply, wherein the power supply is selected from the group of a battery, a fuel cell, an electrostatic couple, a capacitor and a power harvesting device. 
   
   
       19 . The arc suppression system of  claim 15 , wherein the apparatus comprises a power distribution transformer. 
   
   
       20 . The arc suppression system of  claim 15 , wherein the apparatus comprises switchgear. 
   
   
       21 . The arc suppression system of  claim 15 , wherein the apparatus includes a protective element. 
   
   
       22 . The arc suppression system of  claim 15 , wherein the apparatus comprises a high-voltage bushing, the arc suppression device connected to the bushing. 
   
   
       23 . The arc suppression system of  claim 15 , wherein the liquid dielectric fluid comprises a mineral oil, a vegetable oil, a polyolester fluid, a silicone fluid, or mixtures thereof, or other insulative fluids known in the art. 
   
   
       24 . A high-voltage arc suppression system comprising:
 a high-voltage electrical apparatus including a tank and at least one electrical component immersed in a liquid dielectric fluid within the tank;   an arc suppressor device comprising a contact assembly including a line contact, a ground contact spaced from the line contact, and a movable contact mounted stationary to the line contact for normal operation of the electrical component;   an actuator element configured to move the movable contact to complete an electrical connection between the line contact and the ground contact when specified arcing conditions occur in the tank;   a controller operationally connected to the actuator element;   a light detecting sensor coupled to the controller and located to detect a presence of electrical arcing in the tank; and   a current sensor coupled to the controller and monitoring a current flow to the electrical component;   wherein the controller operates the actuator in response to detected arcing conditions, detected current levels, and measured duration of arcing conditions.   
   
   
       25 . The system of  claim 24 , wherein the arc suppressor device is located internal to the tank. 
   
   
       26 . The system of  claim 24 , wherein the apparatus includes a high-voltage bushing, the arc suppressor device connected to the bushing. 
   
   
       27 . The system of  claim 24 , wherein the actuator element comprises a squib. 
   
   
       28 . The system of  claim 24 , wherein the apparatus further comprises a switch and a protective element, the controller programmed to account for operating characteristics of the switch and the protective element prior to operating the actuator in response to detected arcing conditions, detected current levels, and measured duration of arcing conditions. 
   
   
       29 . A method of controlling an arc suppression system configured to detect an occurrence of arcing conditions inside a liquid-filled tank of a high-voltage electrical apparatus, the arc suppression system further configured to sense electrical current conditions in the apparatus and to complete a circuit path to ground when a fault condition is present, the method comprising:
 detecting the presence of electrical arcing inside the tank;   detecting a current level contemporaneous with the detected arcing;   comparing the detected current level to a first predetermined threshold level; and   completing the circuit path to ground when the detected current level exceeds the first predetermined threshold level, thereby extinguishing the detected electrical arcing.   
   
   
       30 . The method of  claim 29 , further comprising:
 measuring a duration of detected electrical arcing;   comparing the measured duration of detected electrical arcing to a predetermined baseline value; and   completing the circuit path to ground only when the measured duration exceeds the predetermined baseline value and when the detected current level exceeds the first predetermined threshold level.   
   
   
       31 . The method of  claim 30 , wherein completing the circuit path to ground comprises detonating a squib. 
   
   
       32 . The method of  claim 30 , further comprising:
 comparing the detected current level to a second predetermined threshold level when the detected current level is less than the first predetermined threshold level; and   completing the circuit path to ground when the detected current level is greater than the second predetermined threshold level.   
   
   
       33 . The method of  claim 32 , further comprising:
 measuring a duration of detected electrical arcing;   comparing the measured duration of detected electrical arcing to a predetermined baseline value; and   completing the circuit path to ground only when the measured duration exceeds the predetermined baseline value and when the detected current level exceeds the second predetermined threshold level.   
   
   
       34 . An arc suppression system comprising:
 means for detecting electrical arcing conditions inside a liquid-filled tank of an electrical apparatus;   means for detecting current flow in the apparatus;   means for measuring a duration of detected electrical arcing;   means for completing a circuit path to ground to extinguish detected electrical arcing; and   means for determining whether to operate the means for completing a circuit path in response to detected current flow and measure arc duration of detected electrical arcing conditions;   wherein the means for deciding responds to certain electrical arcing conditions while ignoring other detected arcing conditions.   
   
   
       35 . The system of  claim 34 , further comprising means for actuating the means for completing the circuit path. 
   
   
       36 . The system of  claim 34 , further comprising means for supplying power to at least a portion of the arc suppression system.